drm: panel: lg-sw43408: Add lab regulator SC notify supportdev/p3_labibb_upstreaming

Lab regulator requires the clients to register for the short circuit
notification sent via REGULATOR_EVENT_OVER_CURRENT.

They should try to enable the regulator on getting this event. If it
doesn't get enabled, they need to assume that short circuit is permanent
and disable themselves.

Add this support to the panel driver, who is a client.

Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>

1 files changed, 65 insertions, 1 deletions

diff --git a/drivers/gpu/drm/panel/panel-lg-sw43408.c b/drivers/gpu/drm/panel/panel-lg-sw43408.c
index d9befd42b995..02495f6548fb 100644
--- a/drivers/gpu/drm/panel/panel-lg-sw43408.c
+++ b/drivers/gpu/drm/panel/panel-lg-sw43408.c
@@ -84,6 +84,8 @@ struct panel_info {
 	struct pinctrl_state *active;
 	struct pinctrl_state *suspend;
 
+	struct notifier_block nb;
+
 	bool prepared;
 	bool enabled;
 	bool first_enable;
@@ -94,7 +96,6 @@ static inline struct panel_info *to_panel_info(struct drm_panel *panel)
 	return container_of(panel, struct panel_info, base);
 }
 
-
 /*
  * Need to reset gpios and regulators once in the beginning,
  */
@@ -416,6 +417,65 @@ pr_err("In sw43408 panel_enable\n");
 	return 0;
 }
 
+static int panel_lab_regulator_event(struct notifier_block *nb,
+				unsigned long event, void *data)
+{
+	struct panel_info *pinfo =
+				container_of(nb, struct panel_info, nb);
+	int ret;
+pr_err("In sw43408 panel_lab_regulator_event\n");
+
+	if (event & REGULATOR_EVENT_OVER_CURRENT) {
+		/* Try to reinitialise the panel, since lab regulator would
+		 * have been disabled by the short circuit.
+		 * if it throws an error, then the panel won't recover;
+		 * shutdown the panel.
+		 */
+		ret = lg_panel_prepare(&pinfo->base);
+
+		if (ret) {
+			dev_err(pinfo->base.dev,
+				"Failed to re-enable lab regulator: %d\n",
+				ret);
+			lg_panel_unprepare(&pinfo->base);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int panel_register_lab_notify(struct panel_info *pinfo)
+{
+	int i, ret = 0;
+	struct regulator *lab_reg = NULL;
+pr_err("In sw43408 panel_register_lab_notify\n");
+
+	pinfo->nb.notifier_call = panel_lab_regulator_event;
+
+	for (i = 0; i < ARRAY_SIZE(pinfo->supplies); i++) {
+		if (strcmp(pinfo->supplies[i].supply, "lab") == 0) {
+			lab_reg = pinfo->supplies[i].consumer;
+			break;
+		}
+	}
+
+	if (lab_reg != NULL) {
+		ret = devm_regulator_register_notifier(lab_reg, &pinfo->nb);
+
+		if (ret)
+			dev_err(pinfo->base.dev,
+				"Failed to register lab notifier: %d\n", ret);
+	} else {
+		dev_err(pinfo->base.dev,
+			"Invalid name while trying to register lab notifier: %d\n", ret);
+
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
 static int lg_panel_get_modes(struct drm_panel *panel,
 			      struct drm_connector *connector)
 {
@@ -635,6 +695,10 @@ pr_err("In sw43408 panel add\n");
 	if (ret < 0)
 		return ret;
 
+	ret = panel_register_lab_notify(pinfo);
+	if (ret < 0)
+		return ret;
+
 	pinfo->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(pinfo->reset_gpio)) {
 		DRM_DEV_ERROR(dev, "cannot get reset gpio %ld\n",